
<script language="javascript">
function initializeBody(){      	
      	// Seteo de proyecciones
		projection = new OpenLayers.Projection("EPSG:900913"); 
       	displayProjection = new OpenLayers.Projection("EPSG:4326");
		var options = {
                projection: projection,
                displayProjection: displayProjection,
                units: "km",
                /*numZoomLevels: 18,
                maxResolution: 156543.0339,*/
                maxExtent: new OpenLayers.Bounds(-20037508, -20037508, 20037508, 20037508.34)
            };
            map = new OpenLayers.Map('map_canvas', options);

        var mapnik = new OpenLayers.Layer.OSM();
        // create OAM layer
        var oam = new OpenLayers.Layer.XYZ(
             "OpenAerialMap",
             "http://tile.openaerialmap.org/tiles/1.0.0/openaerialmap-900913/${z}/${x}/${y}.png",
             {
             	sphericalMercator: true
             }
         );

         // create OSM layer
         var osmarender = new OpenLayers.Layer.OSM(
                "OpenStreetMap (Tiles@Home)",
                "http://tah.openstreetmap.org/Tiles/tile/${z}/${x}/${y}.png"
         );

         map.addLayers([mapnik, oam, osmarender]);
		
		//selector de tipo de mapa
		var selectMapMenu = new OpenLayers.Control.SelectSwitcher({buttonText:'Mapa', width:'100px'});
		
		selectMapMenu.addItem('Calles', function(){map.setBaseLayer(mapnik);});		
		selectMapMenu.addItem('Calles decorado', function(){map.setBaseLayer(osmarender);});
		selectMapMenu.addItem('Aereo', function(){map.setBaseLayer(oam);});
		map.addControl(selectMapMenu);		
		
		}
		
function unloadBody(){
		
		}
</script>